The present invention relates to computerized systems, software and methods for excluding undesirable network transactions. Cloud based security (for example Zscaler® Security Cloud) is an emerging framework to deploy and upgrade security solutions for multiple service subscribers without causing the upgrade delay found in conventional premise security appliances and applications. Cloud based security is the common core of any cloud based service offering and includes in-line inspection of transaction for its customers, meaning that transactions are analyzed in real-time and a decision is made on the spot, whether to allow or block the transaction based on a variety of criteria. Security services such as URL and content-based message filtering, malware scanning, data leakage protection, may be used for this purpose. Additional specific services may be offered through appropriate configuration and monitoring of policies such as usage and bandwidth. A cloud based security system may scan and record hundreds of millions of transactions in a given 24 hour period. Such a large number of transactions would be very difficult to thoroughly inspect for cybercrime related activities on a real-time basis.